JP3486789B2 - Copolymer latex for carpet backing agent - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a latex for a carpet backing agent. More particularly, this invention relates to backing latices that provide high levels of carpet peel strength and excellent blister resistance.

[0002]

2. Description of the Related Art A tufted carpet, which is a typical carpet, is a hemp woven cloth or a woven cloth of synthetic fibers such as polypropylene or a primary base cloth of non-woven fabric, and a fiber bundle of nylon fibers, acrylic fibers, wool, etc. After a backing agent (adhesive) is applied to, a secondary base cloth such as jute is stuck and dried and fixed. The water-based backing agent for carpets is mainly composed of a synthetic copolymer latex binder, an inorganic filler such as calcium carbonate or aluminum hydroxide that gives a feeling of weight, and a thickener that prevents the filler from settling and provides coating suitability. There is.

In recent years, in order to improve the productivity of carpets, in order to dry the applied water-based backing agent quickly,
Carpet makers tend to increase the drying temperature. However, the rise of the drying temperature makes it easy to form a film on the surface of the backing agent layer, so the surface film formed by the pressure of water vapor inside the undried backing agent layer is lifted, and from the texture of the jute of the secondary base cloth. There is a problem that so-called blister (blistering) occurs from the backing agent layer and the commercial value of the carpet is significantly impaired.

On the other hand, the blending ratio of the filler in the backing agent for carpets has become higher due to the recent tendency to reduce costs, which tends to lower the peeling strength of the carpet (peeling strength of the carpet to the secondary base cloth). Therefore, the demand for a synthetic copolymer latex that gives a high peeling strength is increasing. Many means have been proposed in the past for improving the blister resistance, but most of them are methods of blending a heat-sensitive gelling agent-like additive into a copolymer latex, and a typical example thereof is Utilization of organopolysiloxane (JP-B-56-44191), utilization of starch (JP-B-57-30429), utilization of polyvinyl alcohol having heat-sensitive solubility (JP-A-60-149677), etc. .

Various proposals have been made for copolymer latexes for backing agents which give a high peeling strength of carpets. For example, from conjugated dienes, ethylenically unsaturated carboxylic acids and monomers copolymerizable therewith. The resulting mixed monomer is obtained by using a specific ethylenically unsaturated emulsifier, the gel content is 30 to 90% by weight, and the average particle size is 50.
A backing agent composition (Japanese Patent Laid-Open No. 63-270872), which gives good water resistance and normal strength (peeling strength) by using a copolymer latex of 0 to 2000Å, a conjugated diene, an alkyl acrylate and methacrylic acid. Copolymer obtained by polymerizing a mixed monomer consisting of an alkyl ester, an ethylenically unsaturated carboxylic acid and another copolymerizable monomer in the presence of α-methylstyrene dimer and another polymerization chain transfer agent. There is a carpet backing agent (Japanese Unexamined Patent Publication (Kokai) No. 3-121179) which has a combined latex and an inorganic filler as main components and has a soft feeling and high peel strength.

[0006]

However, backing agents using these conventional copolymer latexes have not been able to have both excellent blister resistance and high peeling strength of carpet at the same time. An object of the present invention is to provide a copolymer latex for a backing agent, which further improves the performance of a conventional copolymer latex for a backing agent and provides excellent blister resistance and high peeling strength of carpet at the same time. .

[0007]

In order to solve the above problems, the inventors of the present invention have conducted various studies on the copolymer composition of diene copolymer latex and the production method thereof, and as a result, the conjugated diene of a specific combination has been obtained. A specific amount of mixed monomer in the molecule
Is obtained by emulsion copolymerization in the presence of a reactive emulsifier having an unsaturated group capable of radically reacting with α-methylstyrene dimer, and a copolymer latex having a specific high gel content is extremely useful as a carpet backing agent. It has been found to be useful and surprisingly to provide a desired excellent blister resistance as well as a high peeling strength of carpet, and the present invention has been completed.

That is, the present invention includes: (1) 20 to 70% by weight of an aliphatic conjugated diene, 0.5 to 7% by weight of an ethylenically unsaturated carboxylic acid, and other monomers 23 to 79 copolymerizable with them. Unsaturation capable of undergoing a radical reaction in the molecule of 100 parts by weight of a mixed monomer of 0.5% by weight
A reactive emulsifier having a group of 0.1 to 7 parts by weight and a copolymer obtained by emulsion copolymerization in the presence of 0.1 to 5 parts by weight of α-methylstyrene dimer, and water. Provided is a copolymer latex for a carpet backing agent having a gel content of 70 to 98% by weight. (2) Reactive milk represented by the following formulas (1) to (5)
It is also characterized in that it uses an agent .

[Chemical formula 1]

The present invention will be specifically described below. Examples of the aliphatic conjugated diene used as the copolymer component of the copolymer latex of the present invention include 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene and the like. Most preferred is the use of 3,3-butadiene. The ratio of the aliphatic conjugated diene is 20 to 7
It is 0% by weight, preferably 30 to 65% by weight. If the proportion of the aliphatic conjugated diene exceeds 70% by weight, not only the feel of the carpet becomes too soft, but also the peel strength remarkably decreases, and if the proportion of the conjugated diene is less than 20% by weight, It is not preferred because the copolymer latex having a high gel content of the invention is difficult to obtain.

Examples of the ethylenically unsaturated carboxylic acid used as a component of the copolymer of the present invention include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, etc., and one of these may be used alone or 2 One or more species can be used in combination. The proportion of ethylenically unsaturated carboxylic acid is 0.5 to 7% by weight, preferably 1.0 to 5.0.
%, And more preferably 1.5 to 4.0% by weight.
When the amount of the ethylenically unsaturated carboxylic acid used exceeds 7% by weight, the viscosity of the latex obtained becomes high, and the water resistance of the dry film is remarkably impaired. The amount used in (1) is not preferable because the peel strength of the carpet is significantly reduced.

Further, examples of the monomer copolymerizable with each of the above monomers include: aromatic vinyl compounds such as styrene, α-methylstyrene and vinyltoluene; methyl methacrylate, butyl acrylate, acrylic acid 2 -Ester of unsaturated carboxylic acids such as ethylhexyl, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, diethylene glycol diacrylate, and trimethylolpropane triacrylate: vinyl cyanide compounds such as acrylonitrile and methacrylonitrile;

Halogen-substituted vinyl such as vinyl chloride and vinylidene chloride; vinyl carboxylic acid esters such as vinyl acetate; and vinyl amide compounds such as acrylamide, methacrylamide, N-methylol acrylamide, N-butoxymethyl acrylamide; and the like. . Among these monomers, it is preferable to use styrene, unsaturated carboxylic acid alkyl ester, vinylamide compound and the like.

The proportion of the other monomer copolymerizable with these is 23 to 79.5% by weight, preferably 30 to 70% by weight, and more preferably 35 to 65% by weight. The copolymer latex of the present invention contains 0.1 to 7 parts by weight of a reactive emulsifier having an unsaturated group capable of undergoing a radical reaction in the molecule based on 100 parts by weight of the mixed monomer, and α-. It must be obtained by emulsion copolymerization in the presence of 0.1 to 5 parts by weight of methyl styrene dimer. The reactive emulsifier is represented by , for example , formulas (1) to (5) ,

[0014]

[Chemical 1]

[0015]

[Chemical 2] And the like are preferred.

The amount of these reactive emulsifiers used is required to be 0.1 to 7 parts by weight, preferably 0.5 to 4 parts by weight, based on 100 parts by weight of the mixed monomer used during the polymerization.
If the amount used is less than 0.1 part by weight, the peeling strength of the carpet will be low, and if the amount used exceeds 7 parts by weight, the polymerization stability will be insufficient, and a large amount of aggregates will be easily generated during the polymerization, and the polymerization rate will be high. Also becomes extremely slow, which is not preferable.

In the present invention, the amount of the α-methylstyrene dimer (including dimerized α-methylstyrene and isomers) which is required to coexist with the reactive emulsifier during the polymerization is 100% by weight of the mixed monomer. 0 for the department.
It should be 1 to 5 parts by weight, preferably 0.3 to 3 parts by weight. If the amount used is less than 0.1 part by weight, the peel strength of the carpet will be considerably low, and if the amount used exceeds 5 parts by weight, the emulsion polymerization rate will be extremely slow, which is not preferable.

The gel content of the copolymer used in the present invention is 7
It should be 0 to 98% by weight, preferably 85 to 95% by weight. The gel content of less than 70% by weight of the copolymer is not preferable because the blister resistance is markedly reduced.
If the gel content exceeds 8% by weight, the peel strength of the carpet will be significantly reduced, which is not preferable. The gel content here means that 0.5 g of a diene-based copolymer latex solid dried at room temperature was added to 30 cc of toluene, stirred for about 4 hours with a shaker, and then filtered through a wire mesh of 300 mesh or more. The residue on the wire net is dried and weighed, and the residual amount means a value expressed as a weight ratio with respect to the original solid weight of the latex copolymer.

The gel content of the copolymer can be adjusted by the polymerization method, the copolymerization ratio of the aliphatic conjugated diene, the amount of the chain transfer agent added, etc. The copolymer latex with a high gel content of the present invention can be easily obtained by selecting the polymerization conditions that allow the polymerization at a high polymerization rate at a high polymerization rate. The chain transfer agent that can be used in the present invention is mainly composed of α-methylstyrene dimer, and may be used alone or in combination with other known chain transfer agents used in ordinary emulsion polymerization.

Examples include mercaptans such as octyl mercaptan, n-dodecyl mercaptan and t-dodecyl mercaptan; xanthogen disulfides such as dimethylxanthogen disulfide and diethylxanthogen disulfide; thiuram disulfides such as tetramethylthiuram disulfide and tetraethylthiuram disulfide; Halogenated compounds such as carbon chloride and ethylene bromide and 2-ethylhexyl thioglycyl glycolate,
Examples thereof include α-terpinene, γ-terpinene and dipentene. The high gel content copolymer latex of the present invention can be easily obtained by known emulsion polymerization.

Examples of the polymerization initiator used in emulsion polymerization include persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate; organic peroxides such as hydrogen peroxide, cumene hydroperoxide and benzoyl peroxide. Can be mentioned. A polymerization accelerator may be used in combination with this polymerization initiator. Examples of the polymerization accelerator include reducing agents such as sodium hydrogen sulfite, sodium pyrobisulfite, ferrous sulfate, and L-ascorbic acid.

The emulsifier used in the emulsion polymerization is not particularly limited, and examples thereof include sodium diphenyl ether disulfonate, sodium lauryl sulfate, sodium succinate dialkyl ester sulfonate, sodium rosinate, and the like.
Examples thereof include anionic emulsifiers such as potassium rosinate and sodium salt of alkylnaphthalene sulfonic acid formalin condensate; nonionic emulsifiers such as polyoxyethylene alkyl ethers and polyoxyethylene alkyl esters.

In the copolymer latex of the present invention, the monomer is added in the presence or absence of the seed latex in a batch, either continuously or in a divided manner, in the range of about 30 ° C to 100 ° C. It is obtained by emulsion polymerization at the temperature of. The high gel content copolymer latex of the present invention includes, for example, pigment dispersants such as low molecular weight polycarboxylates and polyphosphates such as sodium hexametaphosphate and sodium pyrophosphate; known antioxidants (antioxidants Emulsions, etc.); Crosslinking agents such as polyfunctional epoxy compounds, blocked isocyanates, melamine resins, polyvalent metal salts and oxazoline compounds; thickeners such as polycarboxylic acid salts, polyether types, cellulose ethers and polyacrylamides; organopolysiloxanes. A blister preventing agent such as an alkylene oxide compound of an alkylphenol formalin condensate; a neutralizing agent for caustic soda or causticum; an antiseptic agent, a defoaming agent, a film-forming auxiliary agent and the like can be added as necessary.

When the copolymer latex of the present invention is applied to an adhesive for lining a carpet, 100 parts by weight of the copolymer latex is added to calcium carbonate,
About 50 to 600 parts by weight, preferably 150 to 500 parts by weight, of one or more inorganic fillers such as clay, talc, aluminum hydroxide, magnesium hydroxide, barium sulfate, magnesium carbonate and titanium oxide; poly (meth) carboxylic acid It is preferable that an appropriate amount of a thickening agent such as salt or cellulose ether and, if necessary, a foaming agent (anionic or nonionic emulsifying agent) are blended and applied (foaming) to the carpet material. Further, the viscosity of the carpet backing agent using the copolymer latex of the present invention is usually 20,000 to 4
It is desirable to adjust with a thickener or water so that the solid content concentration thereof is usually 50,000 cps and 70 to 80% by weight.

[0025]

The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In the examples, parts and% mean parts by weight and% by weight, respectively. (Example 1) 75 parts of ion-exchanged water, 5 parts of acrylic ester-based seed latex (35% solids), and 0 sodium dodecylbenzene sulfonate were placed in a pressure-adjustable pressure reactor equipped with a stirrer that was replaced with nitrogen. .2 parts (solid content),
Charge 1.0 part of itaconic acid (IA) and adjust the internal temperature to 75 ° C. Next, 54 parts of butadiene, 43 parts of styrene 1.0 part of acrylic acid (AA), methacrylic acid (MAA)
1.0 part, tertard decyl mercaptan (t-DD
M) 0.6 part and α-methylstyrene dimer (α-M
SD) A mixture of 0.5 parts of a monomer chain transfer agent and 23 parts of deionized water, a reactive emulsifier (Acroan HS-
1025; manufactured by Dai-ichi Kogyo Co., Ltd.), 0.8 parts of potassium persulfate, 0.8 parts of potassium persulfate, and 0.2 parts of potassium hydroxide are charged into the reactor for 7 hours for polymerization.

Then, the polymerization temperature was raised to 85 ° C. and further about 2
After allowing the polymerization to proceed for a time, a caustic potash solution was added to raise the latex pH to about 8, and a small amount of unreacted monomer was removed by steam distillation to obtain a latex having a solid content of about 48%.
The gel fraction of the obtained latex at room temperature was measured, and the peel strength and blister resistance of the carpet were measured under the following evaluation conditions and methods. The results are shown in Table 1.

Peeling Strength of Carpet A carpet backing agent is prepared with the following formulation. Copolymer latex (solid content) 100 parts Sodium tripolyphosphate 0.25 part Polycarboxylic acid-based filler dispersant (solid content) 0.25 part (Poise 530; manufactured by Kao Corporation) Phenolic antioxidant 1.0 Part Silicone antifoaming agent 0.1 part Heavy calcium carbonate 450 parts Sodium polyacrylate (thickener: solid content) 0.8 part Carboxymethyl cellulose (thickener: solid content) 0.8 part Water proper amount solid Min 74% Viscosity about 18,000cps (B type No4, 12rpm)

1300 g / m ² (wet) of the prepared backing agent on 1/8 gauge original fabric of acrylic loop pile
Apply, then lay 7 ounces of jute on it and dry at 130 ° C. for 15 minutes to make a carpet sample. 5cm width x 1 for the created carpet sample
Cut to a length of 5 cm and apply a tensile tester to 100 mm /
The strength when peeling the jute 180 ° at the speed of minute (the average value of 3 points in order of highest peak and 3 points in order of low peak) is obtained.

Blister resistance A backing agent having the following composition is prepared. Copolymer latex (solid content) 100 parts Sodium tripolyphosphate 0.5 part Polycarboxylic acid type filler dispersant (solid content) 0.5 part (Poise 530; manufactured by Kao Corporation) Phenolic antioxidant 1.0 Part Silicone antifoaming agent 0.1 part Heavy calcium carbonate 300 parts Sodium polyacrylate (thickener: solid content) 0.9 part Carboxymethyl cellulose (thickener: solid content) 0.9 part Water proper amount solid Min 68% Viscosity about 18,000cps (B type No4, 12rpm)

The backing agent prepared above was applied to a Teflon plate with a comb iron (5 mm interval, 5 mm height) and dried in a condition of 180 ° C. for 5 minutes to prevent blistering. The degree of occurrence is visually judged in the following 5 stages. 5 No blister occurrence, 1 many blister occurrence

(Examples 2 to 13) In Example 1, the monomer composition, the type of reactive emulsifier and the amount used, and α-M
A copolymer latex was obtained in the same manner as in Example 1 except that the amounts of the SD and t-DDM chain transfer agents used were changed as shown in Table 1. When the gel content of the polymer, the peel strength of the carpet and the blister resistance of the obtained latex were measured, high peel strength and good blister resistance as shown in Table 1 were obtained at the same time.

Comparative Examples 1 to 7 The same as Example 1 except that the monomer composition or the amount of the reactive emulsifying agent or α-MSD used was changed so as to fall outside the range of the present invention as shown in Table 2. The latex obtained by polymerization by the method and the amount of chain transfer agent as shown in Table 2 were adjusted so that the gel content was out of the range of the present invention. Was measured. The results are shown in Table 2.

[0033]

[Table 1] (Note) A ^* : Aqualon HS-1025 (Daiichi Kogyo Seiyaku Co., Ltd.) B ^** : ADEKA REASOAP SE-1025N (Asahi Denka Kogyo Co., Ltd.) C ^*** : Latemur S-180A (Kao (stock) ))

[0034]

[Table 2] (Note) * Measurement is not possible

From the results shown in Tables 1 and 2, the present invention comprising the composition ratio of the aliphatic conjugated diene monomer within the scope of the present invention, the ratio of the specific reactive emulsifier and α-MSD used, and the specific gel content. It can be seen that the copolymer latex of (1) has a high carpet peel strength and at the same time has excellent blister resistance.

[0036]

INDUSTRIAL APPLICABILITY As described above, the carpet obtained by using the copolymer latex according to the present invention as a carpet backing agent provides a high level of carpet peeling strength and excellent blister resistance.

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) D06M 13/00-15/72 F term (4L033)

Claims (2)

(57) [Claims] 1. A mixture comprising 20 to 70% by weight of an aliphatic conjugated diene, 0.5 to 7% by weight of an ethylenically unsaturated carboxylic acid, and 23 to 79.5% by weight of another monomer copolymerizable therewith. 100 parts by weight of monomer can undergo radical reaction in the molecule
0.1 to 7 parts by weight of a reactive emulsifier having an unsaturated group and α
-Methylstyrene dimer, comprising a copolymer obtained by emulsion copolymerization in the presence of 0.1 to 5 parts by weight and water, and having a gel content of 70 to 98% by weight. A copolymer latex for a carpet backing agent. 2. Shown by the following formulas (1) to (5):
A reactive emulsifying agent is used, The claim 1 characterized by the above-mentioned.
Copolymer latex for carpet backing agent . [Chemical 1]